Piston-type accumulators with gas and fluid sides separated by an axially displaceable piston are known in a plurality of designs. The axially guiding part of the accumulator housing which surrounds the separating piston generally has the shape of a cylinder pipe. For this reason, piston-type accumulators are often called cylinder accumulators. The seal areas on the piston circumference are conventionally formed by ring seals or O-ring seals which are recessed into outer circumferential grooves offset axially to each other in the separating piston.
For use of these cylinder or piston-type accumulators high demands are imposed with respect to their operational reliability, especially over wide temperature ranges, for example, between −40° C. and +150° C. In a generic piston-type accumulator according to DE 101 39 192 A1, within the accumulator housing at a point located between the seal areas of the separating piston, a bleeding possibility has been created for drainage of leaking media passing through the seal areas. As a result of the bleeding possibility between the gas-side and fluid-side seal areas in the known solution, it is ensured that media cannot pass from the gas side to the fluid side or vice versa. In this manner, this piston-type accumulator retains its tightness even under extreme conditions and for long periods of use.
The separating piston formed of a steel material is large in its axial direction of motion within the accumulator housing, and can be considered heavy in terms of weight. As a result of the associated sluggish dynamic behavior of the piston-like separating element, the known hydraulic or piston-type accumulator is less suited for applications in which the separating piston must be moved in a rapid sequence, for example, in the cases in which on the fluid side high-frequency pressure pulses are delivered into the accumulator, and for those cases in which the piston-type accumulator is supposed to entail less weight, for example, in the areas of aeronautics and astronautics.